So, there are a ton of MMOs out there, and I've tried a few, and I don't like any of them, because:

-They rarely have a living world that your actions have any real effect on.

-Before you can do anything interesting you have to spend hours, or days, levelgrinding.

For a while now, I've been thinking about making a forum game set in a world where whatever you do has realistic consequences, and the players are free to do whatever they want (sandbox style), but goals should emerge naturally. There a few things the game should have:

-Ability to have lots of players.

-A simple system for controlling the characters.

-Ability to easily deal with players being inactive.

-As few NPCs as possible - the players should be the driving forces of the world.

-Any role should be available to a player when they join the game, anything from a lowly civilian to an adventurer to a ruler of a nation.

-There should be a living economy formed by supply and demand.

My current thinking is a medieval-fantasy-style world, where the game takes place in a wilderness territory. Players can try to build their own empires, or get whatever job they like in someone else's domain. There wouldn't be any real turns, instead you post your action and as soon as the GM has posted the result you can post a new action. The world would be divided up into a number of smaller regions, with natural resources tracked for each of them.

I was thinking about using a Roll to Dodge system for battles and skill tests, but all the turns of the battles would be fought at once. So a player might say "I go to the Cursed Cave and fight the dragon living there", the GM plays out the entire battle turn for turn, until either side is dead.

@Silverdream

I hope not. You shouldn't have to wait for other players to post their actions before you can go again, you should only have to wait for the GM to post the result of your action. That way inactive players won't slow down the game.

So for example if Tzan's order was drive chariot full with gold to King Goldenbuttoms and my orders would be hide in the bushes next to the road and ambush any body passing by, would we then interact?
I think you should allow orders to also be sent by Pm because sometimes you want to do something in secret.

But really it is just a question of how many people want to play and how much time you want to devote to it.

To riff off of Rody's question here, I feel like a lot of what makes an awesome story-based MMO is its setting; combat and the mechanics should take a backseat, especially if it's forum-based and not limited by the constraints of any sort of program or code. This is part of why live-table gaming with good people is such a commodity; the story is all about the things that you, as a player, do.

That being said (and I don't mean to rain on anyone's parade), but I'm not certain you can make this work, particularly on forums such as this one, where the majority of people are a lot less likely to take something seriously enough to make it count- even when they're trying to. Especially since you can't make any decent threats for those who don't take it seriously and ruin the experience for those of us who enjoy the serious aspect of the atmosphere.